- the KEF Q300
- Monitor Audio RX-1
- if you can bump your budget to the $850 range several nicer options are available.
(Though for strictly music listening, at medium volumes, the Q300 and RX-1 are pretty dxxx good.)
FWIW, the KEF Q300 are only $500 a pair at http://www.accessories4less.com/. Theoretically they are B-stock, but many folks (including myself) on the KEF Owners thread have purchased there and the speakers were always pristine.